Electric switch.



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APPLICATION FILED IIIAY 22. 1916.

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1I Q' Z H. L. BRADLEY.

ELECTRIC SWITCH.

APPLxQATIoN man HAY 22k, 191e.

Patented May 2l, i918.,

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ELECTHIG SWITCH.

APPLlCATlQM FILED MAY 22. 1916. Lff Bamm May 21,19n8- 4 SHEETS-SHEET 3.

H. L mmmf.V ELECTRIC SWITCH.

APPLICATION FILED MAY 22| 1916.

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UNITED STATES PATENT oFnicE.-

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ELEGTBIC SWITCH.

To'aZZ'wwm z't may concern;

Be it known that I, HARRY L. BRADLEY, a citizen of the United States, residin at, Milwaukee,-county of Milwaukee, and tate of Wisconsin, have invented certain new and useful Improvements' in Electric Switches, of which the following is a speciication, reference being had to the accompanying drawings, forming a part thereof.

Myinvention relates to 1m rovements in electricl switches, -particular y that .type which isoperated magnetically.

The usual magnetic switch or contacter I employs amagnet or solenoid by which a movable arm,'carrying one of the contacts of the switch, is moved to make contact with the second contact when the magnet is energized. U on the denergization of this magnet, t e switch falls openl either by gravity or by the action of a spring or a combination of both. The separation of the contacts when the switch falls open is not usually suicient to disrupt the arc unless assisted by some auxilia4 means. This auX- iliary means is genera y in the form of what is termed a magnetic blowout, which consists of an electromagnet with pole pieces so arranged that the path of the lines 'of force' will pass at right angles throughthe path of the arc. The mechanism of these magneticv blowouts which are generally used on magnetically operated switches, can be described as consisting ofA a coil provided with rojecting pole, pieces, which are shielded om contact with .the arc by deliectors of some refractory insulating material. These arc shields or defiectors are in such shape as to formsubstantially a flue or chute through which the .heated gases of the arc are drawn.

l As the formation of an arc must result inl 'a' certain amount of destruction of the contacts, leavin a residuum of oxids and ,other products of eat and combustion, which are of low conductivity, it is therefore quite essential that the contacts be scraped or iiled clean from time to time in order to insure suiciently high conductivity at the points of contact. Y

In order to facilitate the cleaning of these contact points, it is the practice either to make the arc chute and pole pieces removable frm the switch proper or to hin e them in such a manner that they may 5e moved away from their normal location, thus leaving the contacts exposed for in- MILWAUKEE, -wiscorfrsnml l r Patented May 21, 191s-,

Application led Hay 22, 1916. '-Serial No. 99,086.

spec'tion. and repair. This movin of the polev pieces and arc chute awa rom the contacts,with the resultant shi ing of the magnetic field to a point remote from the path of the arc, leaves the switch subject to 'the danger of being operated with the magnetic ,blowout in .an inoperative position. This can be readily brought about throu h accident or carelessness, the result being t e destruction ofthe switch contacts through 4 the continuation of the arc, and not infrequently great damage occurs to the apl aratus to which the switch was connecte and which it was intended to govern.

It is also important that the switch be made as light and compact as possible, that the mass'of the various parts be reduced to a minimum, which tends also to reduce the inertia, both mechanically and magnetically, and resultsin a maximum speed and sensitiveness of operation vwith a low current ilow in the magnetizing coil, which is a very desirable characteristic. It is also an advantage to have the switch occupy as little space as is possible in view of the fact that switches are frequently assembled with other apparatus on switch boards and panels, the dimensions of which are often arbitrarily restricted.

The coil that furnishes the motive power for the operation of the switch, together with its magnetic circuit, are factors that and the path of the magnetic circuit must be as shortI as. the mechanism will permit and of such dimension as to possess a minimum reluctance, for all waste of the magnetic iiux must be oiset by making the coil large and powerful enough to compensatev for the losses.

The objects of my invention are, first, to provide a means for preventing the switch l from being operated when, the magnetic blowout mechanism is not in proper position; second, to provide a means by which the switch contacts can be made readil accessible for inspection and cleaning; t ird, to reduce the leakage or diversion of the ux from the operating coil to a smaller amount than has heretofore been the case in switches of this t e.

To furt er describe my invention, I refer to the following drawings `in which,

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v Figure 1 is a frontl elevation of a switch embodying my invention, front and side elevation, showing the switch with the magnetic blowout coil raised and the contacts' widely separated for inspection in Fig. 3 part of the blowout chute being broken away parts being shown in section. In Fig. 4 the switch is represented in its normally open position with the blowout chute and operating coil partly broken away parts being shown in section. The normally closed position of arm and contact is indicated by dotted lines. Fig. 5 shows the side elevation of a modified form of my device, Aand Fig. 6 shows the section thereof on the line 6-6 looking in the the arrows..

In these figures, a magnetic frame 1 is mounted upon a suitable insulating sup ort 2. This frame carries a projection 3, W ich direction of forms the core of the' magnet on which is tween the tongues of frame 1 an mounted the magnetizing coil 4. Pivoted to the frame-1,

the stop 9 by the spring 10, the contact 11 isl secured to the transverse portion of the -U shaped member 8 and when the switch is closed i`s yieldingly held against the fixed, contact 12 by the spring 10 which yieldingly enga es the member 8. The pivoting of the mova le member 6 by the pivot 5 and the vmember 8 bythe pivot 14 forms a two part movable contact carrying member which causes the contact 11 carried 'thereby to have a yielding rolling contact with the xed contact 12 when brought into engagement therewith which is desirable as maintaining the contacts in good condition. This contact holder 13 is suitably mounted VYipon'the in-Y `sistent with the form of construction, where the magnetic leakage will be at a minimum.

silating support 2.

On the movable member 6 is mounted the conical lmagnetic iezse Y..15 that telescopes with the coil 4 an -'coil supporting projection 3. r,lhis telescoping of the conical piece 15 into the coil 4 is for the purpose of locating the magnetic air gap-"at a ont con- To the? contact holder 13 is .fastened a bracket piece "16 that supports the blowout coil 16l and chute 17. The pole pieces 18 and the attached insulating pieces 19 and 20 that go to form the blowout chute surrounding the contacts 11 and 12 are collectively at 22 to the core 21 of the? blowout chute 17 cannot be lifted from its operative pivoted chute 17in such a manner that the chute Figs. 2 and. 3, a

by means of the pin 5, is' lthe movable member 6, 'which is also of in ag` when open from its operative position. f This stop 17 projects suiciently from the backing plate 2 so that the said chute 17 cannot be opened so far that it will not return to its operative position by the force of gravity.

If desired said Stop maybe, as in the drawing, .combined with a binding post or the chute may be so designed that-a portion thereof will come in contact with the said backing plate before it is lifted so far that it will not return to its operative position by the force of gravity without the use of springs or other Vactuating mechanism. Because of this construction th'e chute is always in operative position except when held up by the operator for cleaning the contacts.

To this blowout chute 17 is attached a motion limiting stop -24 insulated from said chute by a bushing 24 for limitin the motion of the contact 11 and attache movable `arm 6. This stop. is provided with a set screw 23 for adjusting. this motion limiting function. The lifting of the blowout chute and the attached motion limiting stop away from the region of the contacts permits the movable arm 6 andattached contact to drop to a position entirely out of the effective field of the coil 4' as shown in Fig. 3, which effec'- tually prevents the switch being .operated when opened for cleaning 'the contacts. It is apparent that if the blowout chute 17 be lifted and the movable arm 6 be dropped for cleaning, and the operator throughinadvertence release thed blowoutl chute 17 so that `it drops into position before returning the movable arm4 6 toits normal position, the

.conical magneticpiece 15 will be so far from the magnetic coil 4 so as to be unaffected by the magneticl fluxthereof, and consequentlyV v the ixed contact and the movable contact piece 11. By turning the set screw 23 the air gap between the-conical magnetic piece 15v and by putting a resistance vin circuit with the long that the ends thereof farthest fromlthebacking plate 2 will not be cleared bythe motion limiting stop 24, so that the blowout icol )the coil 4 can be regulated so that the switchl v will operate at a predetermined voltage. If desired the same means may be accomplishedJ coil 4 so thatthe desired 'result off having 'the .l

position and the movable contact 11 dropped cleaning and inspection, consisting into the position show-n by dotted lines in Fig. 5, thus retracting the end of the movable contact 11 so that it is cleared-by the motion limiting stop 24, permitting the apparatus to be opened for inspection and cleaning. If it is desired the same means can be accomplished by so locating the movable stop 24 and the set screw 23 that the said set screw will not clear theend-of the movable contact 11 without being unscrewed. I, however, prefer the other formof my device as it unnecessary to disarran e the adjustment of the set screw 23 in or er to enable the device to be opened.

It is apparent from what has been said that there may be two circuits of electricity iowing through my improved switch, the main or motor circuit coming in through the binding post 17', through the coil 16 to the v contact 12, through the contact 11, the lexible wire 27, and the binding post 28, and then out to the main line. The auxiliary circuit passes through the binding post 29 to the coil 4 and out through the blnding post 30, and is so designed that the switch may be controlled from a remote point.

I claim v 1. In an electric switch the combination of a movable member carrying a contact, a contact engaged by a contact on said member when said member is vactuated in one direction, movable means for breaking the arc between said contacts,'and a stop operated by said means limiting the movement of said contact carrying member in the opposite'direction.

2. In an electric switch the combination of a movable member carrying a contact, a contact engaged by a contact on said member when sai member is actuated in one direction, movable means for breaking the arc between said contacts, said means automatically returning to and remaining in its operative position, and a stop operated thereby and limiting the movement of said contact contact carrying member in the opposite direction.

3. In an electric switch the combination of a movable member carrying a contact, a contact hengaged by a contact on said member when said member Iis actuated in one direction, al movable chutev or cell surrounding said contacts, and a stop operated by said chute and limiting the movement of said contact carrying member in the opposite direction. p

4. In an electric switch the combination of a movable member carrying a contact, a contact engaged by a contact on said member when said member is actuated in one direction, a movable chutefor cell surrounding said contacts which automatically returns to and remains in its operative position, and a stop operated by said chute and limiting the movement of said contact carrying member in the opposite direction.

5. In an electric'switch the combination of a movable membercarrying a contact, a contact engaged by a contact on said member when said member is actuated in one direction, a movable chute or cell surrounding said contacts, and a stop attached to said chute and limiting the movement of said contact carrying member in the opposite direction.

6. In an electric switch the combination of a movable member carrying a contact, a contact engaged by a contact on said member when said member is actuated in one direction, a movable chute or cell surrounding said contactswhich automatically returns to and remains in its operative posltion, and a stop attached to said chute and limiting the movement of said contact carrying member in the opposite direction.

7. In an electric switch the combination of 

